The chemical industry has been given an important role in the Reagan administration's selection of a new chief of the Environmental Protection Agency.

The new EPA administrator, not yet chosen, will make decisions that could require the industry to spend billions of dollars on air, water and hazardous waste pollution control.

The EPA job is one of a number of key sub-Cabinet regulatory positions over which there is behind-the-scenes skirmishing by affected industries. Business interests have looked hopefully to the Reagan team to select job-safety, consumer and environmental regulators who are more sympathetic to their problems.

It is unlikely, however, that any of the regulatory appointments will carry as much economic portent for a single industry as the EPA job carries for chemical firms.

By industry estimates, waste cleanup, toxic-substances control, hazardous air and water pollutants, resource-recovery laws and other EPA requirements will cost chemical companies more than $2 billion if fully enforced.

Several decisions on implementation of these statutes await the next EPA administrator. Also at stake will be continuation of regulatory plans and aggressive enforcement programs begun by the Carter administration.

Reagan transition team officials yesterday denied that they have given specific veto power to the chemical industry, but conceded that corporate views are being solicited and weighed on EPA candidates' names.

"Our policy is to involve anyone who has ideas on these matters," a top-level transition officer said.

An official of the Chemical Manufacturers Association (CMA), the major trade group, said, "We've had an opportunity to comment," but he too denied that such a process constituted approval rights.

Officials of several CMA member companies, however, indicated that negative comments about any EPA candidate almost certainly would block his final selection.

The industry's role in the selection process came to light after Frank Oreffice, chief executive of the Dow Chemical Co. and head of the Dow Chemical Co. and head of CMA's executive committee, met last Friday with E. Pendleton James, the top talent scout for the president-elect.

Word spread quickly that Oreffice had spoken against the candidacy of Gordon Wood, a former congressional staff aide who now is a lobbyist with the Olin Corp., a leading chemical firm.

Wood, an attorney and chemical engineer, was portrayed as a moderate in last year's intense congressional debate over creation of a "superfund" requiring companies to pay part of the costs of hazardous chemical waste clean-up.

Dow was one of the industry's more adamant opponents of superfund, and went along with CMA's last-minute disavowal of a compromise bill. CMA President Robert A. Roland said at the time, just after the election, that the industry supported only a minimal version of the superfund bill, regarding subsequent additions as going too far.

The superfund Congress eventually approved without CMA support will be administered by the EPA. In addition to its problems with superfund, Dow has other problems with the EPA. These have led, among other things, to a suit to stop the agency's aerial surveillance of alleged pollution sources and an effort to halt an EPA ban of the toxic herbicide 2, 4, 5T.

Oreffice could not be reached for comment, but a Dow spokesman confirmed that he had discuussed the EPA appointment and industry problems with EPA enforcement in his meeting with James.

Industry insiders interpreted the session as a blow to the candidacy of Wood, whose name is among a number mentioned for the EPA job. Wood declined to comment.

A CMA official said his group had voiced support to inquiring transition-team officials for Rep. James G. Martin (R-N.C.) and Dr. John McKetta, a Texas educator. Both men have removed their names from consideration.

Others reported to be in the running for the EPA post include Dr. James Mahoney, senior vice president of Environmental Research and Techology, a Concord, Mass., consulting firm; Stan Legro, an assistant EPA administrator for enforcement during the Nixon-Ford years, and Henry Diamond, a former New York state natural resources commissioner.